#include <stddef.h>

#define lmem_c
#define LUA_CORE

#include "lua.h"

#include "ldebug.h"
#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"

/*
** About the realloc function:
** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize);
** (`osize' is the old size, `nsize' is the new size)
**
** Lua ensures that (ptr == NULL) if (osize == 0).
**
** * frealloc(ud, NULL, 0, x) creates a new block of size `x'
**
** * frealloc(ud, p, x, 0) frees the block `p'
** (in this specific case, frealloc must return NULL).
** particularly, frealloc(ud, NULL, 0, 0) does nothing
** (which is equivalent to free(NULL) in ANSI C)
**
** frealloc returns NULL if it cannot create or reallocate the area
** (any reallocation to an equal or smaller size cannot fail!)
*/



#define MINSIZEARRAY	4


void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems,
					 int limit, const char *errormsg) 
{
	void *newblock;
	int newsize;
	if (*size >= limit/2)	/* cannot double it? */
	{  
		if (*size >= limit)  /* cannot grow even a little? */
			luaG_runerror(L, errormsg);
		newsize = limit;  /* still have at least one free place */
	}
	else
	{
		newsize = (*size)*2;
		if (newsize < MINSIZEARRAY)
			newsize = MINSIZEARRAY;  /* minimum size */
	}
	newblock = luaM_reallocv(L, block, *size, newsize, size_elems);
	*size = newsize;  /* update only when everything else is OK */
	return newblock;
}


void *
luaM_toobig (lua_State *L) 
{
	luaG_runerror(L, "memory allocation error: block too big");
	return NULL;  /* to avoid warnings */
}



/*
** generic allocation routine.
*/
void *
luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize)
{
	global_State *g = G(L);
	lua_assert((osize == 0) == (block == NULL));
	block = (*g->frealloc)(g->ud, block, osize, nsize);
	if (block == NULL && nsize > 0)
		luaD_throw(L, LUA_ERRMEM);

	lua_assert((nsize == 0) == (block == NULL));
	g->totalbytes = (g->totalbytes - osize) + nsize;
	return block;
}

